Which preposition to use with reminiscing

about Occurrences 2%

Mark was reminiscing about the parting with Steve.

of Occurrences 1%

In an interview with Mrs. Martha J. Jones, she reminisced of the old Civil War days as follows: "I was born in Buckingham County, Virginia, and later during the Civil War, I lived in Gilmer County, W. Va.

Which preposition to use with  reminiscing